The recreational water sports industry has recently adopted alternate means of propelling human powered craft through the application of various foot pedal driven devices instead of traditional paddles and oars. The devices currently employed throughout the industry fall into two general technical classifications.
The first classification adopts a rotary drive mechanism very similar to a bicycle pedal assembly. This pedal assembly is configured to rotate a traditional rotary water propeller through various mechanical transmission configurations. This type of device permits forward and reverse thrust depending on which direction the user is moving the rotary pedal assembly, specifically clockwise or counterclockwise.
The second classification utilizes an oscillating pedal drive input which transmits torque through mechanical linkages to submerged fins which swing through semi-circle arcs beneath the pedal assembly. Due to the nature of this type of device, only a single direction of motion is available and cannot be altered without physically reorienting the device relative to the watercraft.
The recreational water sports industry has identified the benefit of oscillating pedal motion due to its mechanical efficiency and reduced fatigue on the user. Rotating water propellers are preferred within the industry due to their simplicity in design and manufacturing which leads to reduced part and assembly costs. Mating the oscillating input with a rotary propeller output may appear to be a natural progression of prior art, however in prototype devices that convert oscillating input motion into rotary output motion, all attempts have utilized gear trains and clutches which are heavy, noisy, and complicated. The cost of manufacturing a hybrid water thruster utilizing oscillating input and rotary output must correspond to what the recreational water sport market can support, thus a device which can be successfully manufactured and sold must be lightweight and simple in design and execution.